The emergence of Arizona and Connecticut as competitive Senate battlegrounds has reinforced one of the most important themes of this cycle: In a neutral political environment, candidates matter more than ever. &nbsp;

Both open-seat races share similarities that extend beyond the fact that each party was favored to hold one seat until recently. The contests are the latest surprises on the 2012 Senate map, following the open seats in Indiana, North Dakota and Maine — all of which turned into more competitive contests than were originally expected.&nbsp;

Republicans are defending the Arizona seat while Democrats are defending the seat in Connecticut. The parallels are striking, if reversed. A House Member was the early favorite to win the Senate race in a state that leans in favor of his party. But the other party’s candidate has some unique quality that has been able to put this seat in play.&nbsp;

In Democratic Connecticut, former WWE CEO Linda McMahon (R) is over-performing in polls against Rep. Christopher Murphy (D). In Arizona, it is former Surgeon General Richard Carmona (D) gaining on Rep. Jeff Flake (R) in a GOP-leaning state. &nbsp;

“Broadly what you’re seeing in races across the country, it’s hand-to-hand combat. It’s trench fighting,” one national GOP strategist said.&nbsp;

Flake and Murphy have a fundamental hurdle that nearly every ambitious House Member faces in a Senate run: building statewide name identification.&nbsp;

While each are known commodities in Washington, D.C., Flake and Murphy represent a fraction of their states and have had to boost their images. At the same time, their opponents bring unique assets to their campaigns. &nbsp;

For McMahon, the assets are literal. She has deep pockets and made it known in her failed 2010 Senate run that she wasn’t afraid to spend whatever it takes to win. She spent about $47 million on that campaign — giving her residual high name identification — and she is currently up in the expensive New York City television market to sell her message.&nbsp;

Estimates vary on how much McMahon has spent in personal funds this time around, but it is enough that the Democratic Senatorial Campaign Committee and other outside groups are having to spend to help Murphy.&nbsp;

Likewise, the National Republican Senatorial Committee is making TV reservations in Arizona to counter Carmona’s strength: his biography. The Bush-era surgeon general has a decorated background of military and intellectual achievement.&nbsp;

Carmona was unopposed in the Democratic primary and spent the spring and summer stockpiling his war chest. He just announced raising $2.2 million in the third quarter.&nbsp;

Flake, meanwhile, emerged from the late August GOP primary drained. He spent most of last month trying to replenish his campaign coffers and pivoting to the general election. At the same time, Carmona spent most of September telling his personal story. Flake is now on the air, but Democratic outside groups are outspending their GOP counterparts 4-to-1.&nbsp;

Republican swagger about the direction of the race in Connecticut is comparable to Democrats’ optimism about Arizona. But so is their defensive posturing.&nbsp;

Operatives in both parties argue that on Election Day, each state will perform in line with its partisan leanings.&nbsp;

“There’s been some natural tightening, but Republicans still feel confident at the end of the day,” a national GOP strategist said about Arizona.&nbsp;

A national Democrat similarly argued that the party would win the race in Connecticut and noted that the state favors Democrats more strongly than Arizona favors Republicans.&nbsp;

Carmona and McMahon are both banking on their crossover appeal for ticket-splitters.&nbsp;

Carmona was a registered Independent until his decision to run for Senate. In interviews, he prefers long-winded nuanced arguments rather than fiery ideological sound bites.&nbsp;

Republicans charge that he is avoiding taking stands. But they also acknowledge that his profile — Vietnam veteran, medical doctor, law enforcement officer and U.S. surgeon general during the George W. Bush administration — has a strong appeal to men.&nbsp;

It is no secret that Republicans courted Carmona, who once killed an assailant in a shootout, to run for office in the past.&nbsp;

Conversely, McMahon is working to appeal to female voters. The Murphy camp recently went up with an ad tying McMahon to so-called anti-woman policies that have been embraced by prominent Republicans. McMahon responded within 24 hours declaring herself “pro-choice.” &nbsp;

Adding to Democratic concerns is Murphy’s name identification issue. When McMahon lost big in 2010, it was against a statewide officeholder, one-time Connecticut Attorney General Richard Blumenthal. But Murphy has struggled to raise his profile outside of his district.&nbsp; &nbsp;

“We knew this race would be close,” said a source with knowledge of the Murphy campaign’s strategy. “We knew she would have the resources ... to push voters her way while they were only listening to her attack ads.”&nbsp;

The belief among Connecticut and national Democrats is that while McMahon currently has a positive favorability rating, those numbers are soft and susceptible to Democratic negative advertising. &nbsp;

Carmona and McMahon had autumn windows of TV advertising while the other side was dark.&nbsp;

Murphy impressed many with his $3 million third-quarter haul, and Flake has proved to be a strong fundraiser in the past. There is little doubt much of that money will go toward October ad buys. The test for McMahon and Carmona over the next month will be whether they can withstand the negative ad barrages that are on the air now.&nbsp; &nbsp;

The backstop for Democrats in Connecticut is that President Barack Obama won the state by a 23-point margin in 2008. He is not expected to reach those numbers again, but his coattails are a part of the Murphy strategy. Arizona is also not in play at the presidential level, but Democrats have made noise about it becoming competitive, and the longer-term trend favors the party.

Republicans are banking on what they describe as a wealth of opposition research from Carmona’s time as surgeon general, and the Flake campaign has sought to tie Carmona to Obama, who helped recruit him.

Connecticut has not elected a Republican Senator since 1982, and Arizona’s last Democratic Senator was elected in 1988. In a wave election year, though, it would not be noteworthy that either Senate race is in play. It has happened before. In 2006, Sen. Jon Kyl’s (R) re-election raised some concern among Republicans, even though he pulled ahead safely. And McMahon gave Democrats a scare in 2010.&nbsp;